The present disclosure relates to a developing device for supplying toner to an image-carrying member, and relates to an image forming apparatus including the developing device.
In general, an electrophotographic image forming apparatus includes a developing device that supplies toner to a drum-like image-carrying member such that it carries a toner image. The developing device is rotatably supported in the state of being opposed to the image-carrying member. To increase the image forming speed, it is necessary to increase the rotation speed of the image-carrying member.
Due to a restriction of a supply speed of toner from the developing roller to the image-carrying member, the density of the toner image on the image-carrying member tends to be less sufficient as the rotation speed of the image-carrying member becomes higher. There is known a developing device that, for the purpose of solving the problem of insufficient density, includes two developing rollers arranged from the upstream side to the downstream side in the rotation direction of the image-carrying member.